Roofing products are often divided into three broad groups: shingles, roll roofing, and underlayment. Shingles and roll roofing typically function as outer roof coverings designed to withstand exposure to weather and the elements. Shingles and roll roofing generally contain the same basic components which provide protection and long term wear associated with asphalt roofing products. These components include a base material made from an organic felt or fiberglass mat which serves as a matrix to support the other components and gives the product the required strength to withstand manufacturing, handling, installation and service in the intended environment. An asphalt coating formulated for the particular service application is often applied to the base material to provide the desired long-term ability to resist weathering and to provide stability under temperature extremes. An outer layer of mineral granules is also commonly applied to the asphalt coating to form a surface exposed to the weather which shields the asphalt coating from the sun's rays, adds color to the final product and provides fire resistance.
Asphalt shingles are among the most commonly used roofing materials. Such shingles are typically manufactured as single layer strip shingles, laminated shingles having two or more layers, interlocking shingles and large individual shingles in a variety of weights and colors. Such laminated asphalt shingles are also often referred to as composite shingles or as architectural shingles or dimensional shingles. Even though asphalt shingles offer significant cost, service life and flammability advantages over slate or wood shingles, slate or wood shingles are still often preferred due to the pleasing aesthetic appearance of a slate or wood shingled roof. An important aesthetic advantage of such slate or wood shingles is their greater thickness as compared to composite shingles. The thickness of slate or wood shingles results in a more pleasing, layered look for the finished roof.
Various composite shingles have been developed that have tabs in one or more layers. Examples of such composite shingles are shown in U.S. Pat. No. 1,894,614 entitled Strip Shingle, U.S. Pat. No. 3,921,358 entitled Composite Shingle; U.S. Pat. No. 4,869,942 entitled Trilaminated Roofing Shingle; U.S. Pat. No. 5,195,290 entitled Laminar Roofing Product; U.S. Pat. Appl. Publ. No. 2002/0178679 entitled Shingle for Optically Simulating a Tiled Roof; U.S. Pat. No. 6,679,020 entitled Multi-Layered Shingle and Method of Making Same; U.S. Pat. Appl. Publ. No. 2004/0123537 entitled Shingle with a Rendered Shadow Design; U.S. Pat. No. 6,038,827 entitled Trilaminate Roofing Shingle; U.S. Pat. No. 6,804,919 entitled Backer for Tabbed Composite Shingles; and U.S. Pat. No. 7,082,724 entitled Packaging of Tabbed Composite Shingles have a Backer Strip Containing Uniform, Identically Spaced, Vertical Projections on its Top Edge.
U.S. Pat. No. 3,921,358 discloses a two-layer composite roofing shingle. The upper layer has a headlap and a buttlap from which tabs are cut out. The tabs may be of varying breadths. The lower layer is an elongated strip that does not have tabs and is positioned below the buttlap and partially overlapping the headlap. The two layers may be of varying colors. The arrangement is intended to provide a shingle of variable thickness that simulates a wood shingle.
U.S. Pat. No. 4,869,942 discloses a three layer shingle. The upper layer has a tabbed edge. The middle layer (or shim sheet) has identical tabs to the upper layer and the two layers are disposed to overlap. The third layer is placed below the second layer and is a continuous strip without tabs. The cut outs are therefore two layers deep. The arrangement is intended to provide improved aesthetic appearance.
U.S. Pat. Appl. Publ. No. 2002/0178679 discloses a laminated shingle in which the upper layer includes a headlap and a buttlap from which tabs are cut out. The lower layer has no tabs and is placed below the buttlap and partly below the headlap of the upper layer. The edge of the lower layer may have a curving contour to match the shape of the lower edge of the tabs in the upper layer. When arranged in courses in a roofing system the lower layer and the overlaying tabs are arranged above the headlap of the vertically adjacent shingle in the lower course and are offset such that the headlap tabs of the shingle in the upper course align with the tabs of the headlap of the shingle in the lower course. The arrangement is intended to simulate a tiled roof.
U.S. Pat. No. 6,679,020 discloses tabbed laminated shingles composed of at least three layers. The layers of each laminated shingle are arranged such that the tabs of each layer are directly on top of one another. The tabs may be of unequal breadths. The tabs constitute the buttlap of the laminated shingle and when arranged in a roofing system these tabs overlap the headlap portion of the shingle in the lower course. The overlapping arrangement is intended to simulate a wooden shake roof.
U. S. Pat. Appl. Publ. No. 2004/0123537 discloses a laminated shingle in which the upper and lower layers are different. The upper layer includes a headlap and a buttlap from which tabs are cut out. The lower layer has no tabs and is placed below the buttlap and partly below the headlap of the upper layer. When arranged in courses in a roofing system the lower layer and the overlaying tabs are arranged above the headlap of the vertically adjacent shingle in the lower course. The tabs and lower layer have areas of darker coloration in order to simulate shadows. This is intended to provide a three-dimensional effect with greater apparent depth.
U.S. Pat. No. 6,038,827 discloses a trilaminated shingle in which all three layers are different. The anterior and middle layers have non-identical tabs whilst the posterior layer is an undivided strip that may have indentations. The anterior tabs are disposed over the middle tabs, but the tabs are not coextensive. All three layers are visible in the laminated shingle and the layers have different colors. This is intended to duplicate the effect of more expensive individual shake or slate shingles.
U.S. Pat. Nos. 6,804,919 and 7,082,724 disclose a composite shingle unit that includes a top and a bottom layer in which both layers have tabs. The layers are arranged such that the tabs of the lower layer point in the opposite direction to the tabs of the upper layer, providing lower layer tabs that are aligned with the gaps between tabs in the upper layer and the ends of the upper layer tabs are aligned with the straight edge of the lower layer. This is intended to create a shingle with an improved nailing zone for attachment to a roof.
Each of the above-referenced patents and patent applications is incorporated herein by reference in their entirety for all purposes within this application.